Method and apparatus for freezing products and the frozen products



Sept. 15, 1970 c. FIELD 3,528,257

METHOD AND APPARATUS FOR FREEZING PRODUCTS AND THE FROZEN PRODUCTS FiledJune 5, 1968 4 Sheets-Sheet l l H 23 35 27 I45 l2 25 I E J II I I:- HHuh,

l3 l3 l3 ZOI Fig.l

INVENTOR. Crosby Field BY eu/zfi flmmgdwlld ATTORNEYS Sept. 15, 1970 c,F|E| D 3,528,257

METHOD AND APPARATUS FOR FREEZING PRODUCTS AND THE FROZEN PRODUCTS FiledJune 5, 1968 INVENTOR. Crosby Field 621/105, Mann/l9 af q ofiti T RNESept. 15, 1970 c. FIELD 3,528,257 I METHOD AND APPARATUS FOR FREEZINGPRODUCTS AND THE FROZEN PRODUCTS Filed June 5, 1968 4 Sheets-Sheet I5INVENTOR. Crosby Field BY auzf/s, Map/z a 34 46124 A T TOR N E 5 Sept.15, 1970 c. FIELD I METHOD AND APPARATUS FOR FREEZING PRODUCTS AND THEFROZEN PRODUCTS 4 Sheets-Sheet 4 Filed June 5, 1968 INVENTOR. CrosbyField BY 61/1195, 11/00/213 &' M124 ATTORNEYS United States Patent()flice 3,528,257 Patented Sept. 15, 1970 3,528,257 METHOD AND APPARATUSFOR FREEZING PRODUCTS AND THE FROZEN PRODUCTS Crosby Field, 8029 HarborView Terrace, Brooklyn, N.Y. 11209 Filed June 3, 1968, Ser. No. 734,126Int. Cl. F25c 1/14 U.S. Cl. 62-72 20 Claims ABSTRACT OF THE DISCLOSURE Amethod and apparatus for extremely rapid freezing and the product itproduces. Thin layers of product are frozen and subcooled on a flexiblestrip in consecutive layers. The product is then removed from the stripand processed.

SPECIFICATION This invention relates to the art of congealing, anddiscloses new products, the method of producing them,

' and the apparatus required.

It is known that rapid freezing of many liquids, especially liquidcomestibles, retains many of the constituents either lost altogether, orat the best changed in some deleterious fashion, when the liquid isfrozen slowly. It has also been found that as a rule, the more rapid thefreezing, the more nearly does the thawed frozen product resemble theoriginal liquid prior to freezing.

This invention discloses a method of extremely rapid freezing, and theproduct it produces is superior to present fast frozen products, becauseit is not only frozen very rapidly, but is immediately subcooled to adegree that prevents partial melting and resultant evaporation as wellthe more rapid sublimation to be found with products nearer the meltingpoint.

For example, liquid eggs are usually frozen in cans requiring from 18 to72 hours to complete the freezing; by the method disclosed hereinseveral seconds are all that is required to freeze the eggs and subcoolthe product.

By the method and with the equipment disclosed hereinafter, a thin layerof liquid egg has been frozen in approximately two seconds, and thensubcooled to the desired degree in another two to three seconds. As thisproduct is too thin to handle as a separate ribbon or when processedinto flakes, another layer of liquid egg is spread on the top of thealready frozen and subcooled layer which immediately freezes to thelayer beneath it, and this layer in turn is promptly subcooled.Proceeding in this fashion enough layers are added to make a ribbon ofthe thickness desired for subsequent handling.

As these layers are extremely thin, the total resistance to heat flowthrough the freezer and the layers varies little with the additionallayer thus spread, as the number of layers required in most cases issmall. For example, frozen ribbons of liquid egg between four and sixone hundredths of an inch thick, comprising four layers, well bondedtogether to form a single homogeneous frozen egg ribbon, has been frozenin ten to fifteen'seconds.

Subsequent handling takes one of two general forms; the frozen productmay be converted into flakes, and thus packed and marketed, or thesubcooled ribbons may be stacked in the form of a bar, wrapped andpackaged. As long as the bar is maintained at its subcooled temperature,the ribbons will maintain their separate identity, and will thaw mostrapidly, as the entire surface of each ribbon will be presented to thematerial being cooled. Contrast this with the present methods ofthawing, requiring so long a time that bacteria growth is favored, or ifthe chunks of frozen material be taken from the can and broken up, laborand possible injury to the egg results.

Both the bar and the flakes disclosed herein have the advantage of largesurface and quick thawing, the bar has the added advantage of having avolumetric density almost equal to that of the solid mass.

The products obtained by this invention are new, but the equipment forproducing them is a substantial improvement over the equipment disclosedin my United States Letters Patents Nos. 2,610,479 and 2,610,476, issuedSept. 16, 1952; No. 2,990,196, issued June 27, 1961, and No. 3,037,366,issued June 5, 1962. Some components of the equipment disclosed in thisapplicaiton, moreover, are related to those disclosed in my copendingapplication Ser. No. 691,055 (series of 1960), filed Dec. 15, 1967.

An object of this invention is to obtain improved frozen products.Another object of this invention is to produce frozen products that maybe very rapidly thawed, when further processed. Still another object isto provide frozen comestibles that can be readily packaged for presentday frozen food markets. These and other objects will be in part obviousand in part pointed out hereinafter.

In the drawings:

FIG. 1 shows a side elevational view of a freezer embodying myinvention;

FIG. 2 illustrates diagrammatically the refrigeration system of thefreezer shown in FIG. 1;

FIG. 3 illustrates diagrammatically the system employed for feedingliquid to be frozen to the freezer;

FIG. 4 is an enlarged view of a portion of FIG. 3 showing the damstructure illustrated therein in greater detail;

FIG. 5 is a sectional view taken along the lines 5-5 of FIG. 4;

FIG. 6 illustrates diagrammatically the system for tracking employed inthe freezer of FIG. 1;

FIG. 7 illustrates diagrammatically the belt lubricating system alsoemployed in the freezer;

FIG. 8 illustrates diagrammatically the drive system employed in thefreezer apparatus;

FIG. 9 is a fragmentary view of the drive pulley used in the freezershown in FIG. 1;

FIG. 10 illustrates diagrammatically apparatus to make flakes from thefrozen ribbons formed in accordance with the teachings of my invention;

FIG. 11 is a sectional view of the line 1111 of FIG. 10; and,

FIG. 12 is a schematic view of an arrangement for cutting the frozenribbons of this invention into strips.

Referring particularly to FIG. 1 of the drawings, the freezer has anevaporator 1 assembled with an evaporator frame 3 in the manner morefully described hereinafter. The subassembly of evaporator 1 andevaporator frame 3 is supported by a base frame 5 bolted to it by meansof brackets 7. Wooden skids 13 form an insulating foundation for themetal base frame 5. This frame has two central support members 6 and 8which carry two centrally supported tubular arms 10', which in turn,support slant portions of the frame 5 cantilevered on both sides. Theslant portion carries a freezing subassembly. The evaporator subassemblyis mounted in a slant position as shown. Pads of rubber 9 providecushioned mountings on the brackets 7 that permit final adjustment ofthe alignment of the evaporators 1 by means of bolts 11, which by meansof their nut 12 control the compression of the pads 9.

As best shown in FIG. 1, a weldnut 21 is bolted to the upper end offrame 5 and supports four parallel guide rods 23, two on each side. Theguide structure is completed by end plate 25 secured to the ends ofguide rods 23 by screws 27. Bearing 'block 31 is bored to slide on guiderods 23, thus permitting the bearings to move longitudinally of theslant frame. Each of the pair of beaning blocks 31 has a bearing 33 foran idler shaft 35. Mounted upon a free turning shaft is an idler pulley37. A drive pulley 19 of considerably greater diameter than the idlerpulley 37 is keyed to a shaft 17, which is rotatably mounted in the pairof bearings 15 secured to the lower ends of the slant members of frame5. Freezing belt 39 is supported by pulleys 19 and 37 and is tensionedbetween them as will be described more fully hereinafter. Movement ofbelt 39 is imparted to it by drive pulley 19. Poulleys 19 and 37 are ofrigid metal and have their cylindrical faces covered by a layer 41 of anelastomer, such as rubber (see FIG. 9). Pulley 19 is driven as describedhereinafter in connection with FIG. 8. The frame is built so that theline between the centers of the shafts of the pulleys 19 and 37 may makewith any horizontal line any angle between 45 above to 45 belowhorizontal. As pulley 19 turns, it drives the belt 39 so that it isdrawn along the curved top surface of the evaporator. The portion of thebelt in contact with the evaporator is maintained at a low temperature.As shown in FIG. 6, the belt is held under tension by rods which bearupward against bearing blocks 31. The force on the inner rod 43 isproduced by a coaxial spring 45 which is screw adjusted for changing thepressure. The force on the outer rod 43 is produced by a coaxialhydraulic cylinder 47 which is automatically controlled as describedhereinafter. The belt is driven by pulley 19 in a clockwise direction inFIG. 1; that is, with the upper run moving to the right.

As shown in FIGS. 4 and 5, each edge of belt 39 has bonded to it acontinuous molded darn structure 49 of an elastomer, e.g., rubber. Asshown in the cross sectional view of FIG. 4, this darn structure hasportions on both sides of the belt; the one portion to retain the liquidor fluid 40 (product) being congealed upon the congealing surface andthe other portion to retain the liquid heat transfer lubricant 42 whichacts both as a lubricant and as a heat transfer agent between the metalof the belt and the evaporators. By maintaining a thin film of heattransfer lubricant on the undersurface of the belt, any irregularitiesin the surface in normal contact are compensated for.

The dams 49 are formed with a thinner section on the product side thanon the lubricant side. This prevents the edges where the dams 49 meetthe metal belt 39 at points 44 from getting cold enough for the product40 to freeze along its edges.

From drive pulley 19, shaft 17 fastened to it by key 18, is extendedinwardly beyond bearing 15 (see FIGS. 1 and 9) where sprocket 51 iskeyed to it. Sprocket 51 is driven from upper jack-shaft 53 by chain 55and sprocket 56 which is keyed to jack-shaft 53. Jack-shaft 53 is turnedby sprocket 57, driven by chain 63 from motor 291, gear-motor sprocket59 and gear motor shaft 61. Jackshaft 53 turns in two bearings '65,bolted one on either side to the center post of frame 5. A lowerjack-shaft 67 turns in two bearings 69 which are similarly bolted to thecenter post of frame 5. Jack-shaft 67 is turned by sprocket 71 fromchain 63. A hydraulic pump sprocket 73 is driven from this jack-shaft bya chain 79 and a sprocket 75, and 73 and chain 79. The sprocket 81 ofthe lubricant pump is also driven by chain 63. Vertical adjustment ofsprocket 81 produces the proper tension in the chain 63. Proper tensionin chain 55 is maintained by vertical adjustment of bracket 87 whichsupports an idler sprocket 83 and its pivot 85.

REFRIGERATION OF EVAPORATOR .FIG. 2 is a diagrammatic representation ofthe refrigeration system for the evaporator 1 which omits accessoriessuch as controls, oil separator and others well known in the art. Liquidrefrigerant from condenser 147 is fed through conduit 149 into the surgedrum through valve 151 which is controlled by level responsive element153 so that the level in the surge drum is maintained at level 155,which is the optimum operating level. The refrigerant liquid flows bygravity from the surge drum into the evaporator 1. The surge drum isconstructed as disclosed in my Pat. No. 3,037,366. The refrigerant vaporformed in the evaporator flows through conduit 157 into surge drum 145,displaced by liquid refrigerant under the static head at level 155. Theliquid refrigerant flows thtrough an orifice in a nozzle into each ofthe evaporator tubes 97 to provide proper distribution of refrigerantbetween the tubes and to increase velocity and turbulence thereinresulting in a higher rate of heat transfer as disclosed in my Pat. No.3,037,366. The refrigerant vapor returns to the compressor 171 via thesurge drum where any liquid carried With it is separated out before itenters the suction line 163. Oil return is obtained by bleed off tubesfrom the lower evaporator header through the oil still 169 and back intothe suction line to compressor 171. Oil still 169 is heated by a smallamount of discharge gas from compressor discharge line 173 through tubes175 and 177 to the top of surge drum 145.

LUBRICANT SYSTEM FIG. 7 is a diagrammatic representation of the systemwhich maintains a thin film of heat transfer lubricant between theevaporator and the belt. This lubricant may be an anti-freeze compoundsuch as an aqueous solution of propylene glycol. A supply of lubricantis maintained in reservoir 179. When the belt is driven, pump 181supplies lubricant to the leading end of the evaporator 1, throughfilter .182 via capillary 183 and a feed block (not shown).

Pump 181 is driven by sprocket 8,1 as previously described withreference to FIG. 8. Used lubricant is re turned to reservoir 179 via adrain line 185.

When the refrigerant flow is stopped a timer keeps the belt 39 runningfor a preset period. During this period solenoid valve .197 opensdiverting all lubricant from the discharge of the pump -181 to reesrvoir179 While the above described lubricant system returns the lubricant inuse to reservoir 179 also to prevent loss of lubricant by overflow onshutdown.

Since the lubricant used is water soluble, it may be gradually dilutedby moisture condensed from the air as the ice maker operates. Further,since the freezing point is raised by dilution, this accumulation ofwater must be constanting removed to avoid possible freeze-up. Since theboiling point of the lubricant and water mixture is a function of itswater content a rectifier 199 is used, maintained at a practicallyconstant temperature by means of an electric immersion heater andthermal switch. The temperature of the rectifier is set to correspond tothe boiling point of the desired concentration of lubricant solution. Asmall convection flow in tubes 20-1 maintains the solution concentrationin reservoir 179 substantially the same as that in rectifier 199 withoutheating the solution in the reservoir. Thus when the solution is dilutedin the reservoir 179, it is also diluted in rectifier 199 depressing itsboiling point below the rectifier temperature. The boiling in thereservoir drives water out of the solution, thus concentrating it untilits boiling point reaches the predetermined rectifier temperature, atwhich time the boiling stops. A reflux condenser 203 having glass ballpacking is used over the rectifier to minimize loss of lubricant carriedoff by the escaping steam.

HYDRAULIC TRACKING SYSTEM FIG. 6 is a diagrammatic representation of thehydrau lic tracking system which automatically keeps belt 39 centered onevaporator 1 and drive pulley '19 and idler pulley 37 as it runs. Areservoir 205 holds a supply of hydraulic fluid. Pump 207 (driven bysprocket 73 in FIG. 8) draws fluid from reservoir 205 to build uppressure in pressure line 209, limited by a pressure regulator 211 whichbleeds into a drain line 213 to return spent fluid to reservoir 205. Thebelt is tracked by using this pressure in the following manner: acontrol valve 215 is operated by a roller arm 217 which follows themolded edge 49 of belt 39. When belt 39 starts to the left of center itcauses arm 217 to turn control valve 215 so as to permit more fluid intocylinder 47 increasing the tension slightly in the left side of the belt39 which moves the belt back to the center position. When belt 39 startsto the right of center it causes arm 217 to turn control valve 215 so asto vent fluid from cylinder 47 decreasing the tension slightly in theleft side of the belt 39 which moves the belt back to the centerposition. Spring 45 maintains a practically constant preset tension onthe right side of the belt. The changes in tension on the left side ofthe belt required for tracking are referenced to this tension and are soslight that they have no noticeable effect on the belt. .A check valve201 is provided between the control valve 2:15 and the cylinder 47. Thisvalve remains open as long as there is pressure in line 209. When thepump stops and its pressure falls, check valve 221 closes to holdcylinder 47 in the proper position for restarting without excessivetracking movement.

FEEDING TH'E LIQUID TO BE FROZEN The feed of the liquid to be frozen isall important. The liquids vary greatly in viscosity, density, surfacetension, and size and amount of suspended solids. Viscosity, density,and surface tension in turn 'vary with the temperature range throughwhich the liquid passes as it is being cooled on the belt just prior tofreezing. In FIG. 3 there is disclosed an arrangement which isapplicable to a large number of liquids.

Referring now to FIG. 3, the freezing belt 39, travelling in thedirection of the arrow 30:2, passes under the following structure.Attached to the main frame 5 are two rods, 303 and 303a, on which slidesin bearings 401 and 402, and 401a and 402a, a frame 304 comprisinglongitudinal members 305 and 305a, and transverse members 306 and 306a.A number of brackets 307 (307b, 3070), are attached to the longitudinalmembers 305 and 305a, and these carry by means of adjustable screws andnuts, such as 308 and 308a, a number of belt wipers 309, 309a, 309b, and3090. The belt wipers are similar to automobile windshield wipers; butwhen intended for food freezing, the blades are made of some materialother than natural rubber, such as silicone rubber.

The brackets 307, et seq., carry clamps 310, 310a, 310a, which in turncarry the open ends of the flexible tubes 3.11, 31l1a, 311b, 311a. Theother end of each of these tubes 311, et seq., is connected to one of aseries of pumps 215, et seq., driven by motors 326, et seq. Suction ofthe pumps 325, et seq., is connected through a header 312 to a reservoir315, which holds the product to be frozen. As temperature control is avital part of the process, reservoir 3.15 is maintained at the requiredtemperature by either heating or cooling coils 3116.

Frame 304 is made to reciprocate laterally by means of a motor 317,carrying a disk 318, in which are a number of holes 319, in one of whicha pin 320 can be inserted, giving a reciprocating motion to the link321, pivoted at 322 to a bracket 323 attached to the frame 304.

Valves, cocks or some similar devices, 3214, 324a, 324b, 3240 are usedto control the flow of the liquid being frozen. :With certain products,such as liquid eggs, albumen will tend to clog up the cock, requiring agreater force to drive it through the cock. For this type of product theconstruction shown is preferable, as it permits changes in pressure inany one line without affecting any other line, in other words, itpermits independent pump action.

The method of operation is: the liquid to be frozen, 328 is fed throughthe tube 311 (see FIG. 5) and is spread by the wiper blade 309 forming asmall puddle in front of the wiper, where it is instantly frozen (324).It is scalloped on the edges because of the reciprocating motion of thewiper described hereinabove. The size of these scallops can becontrolled, as the amount of reciprocation is controlled by the hole 319in which the pin 320 is placed, as each hole 319 is at a differentradius from the center of the disk.

In case, during adjustment, or because of some other incident not normalto the operation, some liquid overflows the ends of the wipers 309, itis caught by longer stationary wiper 330, held by bar 331 by adjustablescrews and nuts 332. Bar 331 is attached to the main frame 5 of themachine by brackets 333, 3330.

For certain products, because of lesser viscosities, the product to befrozen may be flowed on to the belt 39 through a nozzle attached to eachof the tubes 331, et seq. These nozzles may be made of glass, stainlesssteel or other special material.

The reciprocating of the wipers prevents the blades from being frozen tothe moving belt by the quick freezing of the liquid; it also assistsmaterially in flowing the liquid towards the ends of the blades, andproducing a thin film of uniform thickness to be frozen.

Referring now to FIG. 10, it will be seen that the frozen product 324 isin the form of a homogeneous ribbon, sufliciently thick to peel from thebelt 39 as it passes over the deflecting pulley 37, as it has been builtup during freezing as described hereinabove by spreading upon a quickfrozen and subcooled extremely thin ribbon another thin liquid ribbon,which in turn is very rapidly frozen; and this process has beencontinued until the ribbon is sufliciently thick to permit peeling ofthe frozen composite ribbon. It may be discharged into a cold room, andthen broken or cut into lengths manually or by a machine. These ribbonsmay be stacked and wrapped and sold as a bar. If the bar has been keptat the required subcooled temperature throughout the handling, packingand storage, the individual ribbons will not freeze or stick together,and when the package is opened, the individual ribbons will separate andpresent to the material being processed the complete surface of eachindividual ribbon. The entire bar will then thaw extremely rapidly.

To further process the ribbons into flakes, (see also FIG. 11), a chute351 is provided against one side 352 of which ribbon 324 rubs and breaksinto relatively large pieces which fall until they are caught by pins354 and 357, held in brackets 353 in the sides of the chute 351. Pins359, rapidly rotating on shaft 358 break these pieces of frozen materialinto flakes, by hurling them against the stationary pins 354 and 357,whereupon the flakes thus formed fall through the outlet 360 into arefrigerated storage. Shaft 358 is driven by pulling 371 and turns inbearings 367 and 369.

To prevent the subcooled ribbon touching a warm side of the chute anevaporator 363 is provided and a duct 361, together with a fan 365blowing the air through the evaporator and thence against the chute 351.This air is circulated all about the chute, and the methods of doingthis scribed herein.

In the embodiment of FIG. 12 an arrangement is provided for cutting theribbon 324 into predetermined lengths and assembling them in subcooledcondition for storage and shipment. With this arrangement a cutter unit401 has a cutter blade 403 positioned adjacent the side Wall 405 of anassembly tray 407. Knife 403 is carried by a mounting arm 409 which isswingably supported by a pivot 411. A tension spring 413 urges arm 409upwardly and a rotary cam 415 is turned at spaced intervals of time toswing knife 403 downwardly against the tension of spring 413. Duringeach downward movement knife 403 severs the end of ribbon 324 andproduces a rectangular sheet 417 of the frozen product. Ribbon 324 isshown in FIG. 12 as it projects from the freezing surface and is movingat a constant speed. The interval between successive impacting actionsof dam 415 is such as to permit the desired length of the robbon toproject beyond the knife to substantially the opposite wall 419. Hence,the ribbon 324 is cut into predetermined lengths and the sheets areassembled in a stack. When a predetermined number of the sheets havebeen assembled the stack is removed and packaged. The entire assembly ofFIG. 12 is positioned within the subfreezing atmosphere of the airstream in hood 361 and the packaging operation is also at a subfreezingtemperature.

The present invention is applicable to a Wide range of products, i.e.,eggs or the yolks or whites of eggs, fruit and vegetable juices, coflee,cream, and various liquid and viscous products. The term freezing asused herein covers the broad range of congealing fluid products. Thewater in such products is frozen into small crystals. In general, eachfilm freezes immediately and is dry as it moves beneath the next set ofwipers. Illustratively, for products such as eggs, the thickness of eachfilm of the fluid is of the order of .01 to .02" and the ribbon ispeeled at a thickness of the order of .05" to .25". For most products,the ribbon has at hickness which is not greater than .1". As a specificexample, when freezing coffee having solids by weight the film thicknessis .005" to .01" and the ribbon is peeled at .04" to .05".

What is claimed is:

1. In the art of freezing products, the steps of, producing asubfreezing temperature condition upon a flexible surface, depositing astream of the fluid to be frozen onto said surface at a zone spaced fromopposite side edges thereof, imparting to the fluid at said zonerelative motion with respect to said surface to spread the fluid towardsaid side edges to a depth of the order of .005" to .02" thereby to forma first layer of fluid while simultaneously moving said surface withsaid layer thereon parallel to said side edges toward a second zone andpermitting said first layer of fluid to freeze to produce a first frozenlayer, depositing a second stream of the fluid onto said first frozenlayer at said second zone to a depth of the order of .005" to .02"imparting to the fluid at said second zone relative motion with respectto said surface to spread the fluid toward said side edges to apredetermined depth thereby to form a second layer of the fluid oversaid first frozen layer, permitting the fluid of said second layer tofreeze and thereby to form a composite frozen layer comprising saidfirst frozen layer and said second layer, and deflecting said surface topeel it away from said composite frozen layer.

2. The method of freezing eggs which comprises the steps described inclaim 1 wherein each film of the fluid has a thickness of the order of.01 to .02".

3. The method as described in claim 2 which includes additional steps ofdepositing and spreading and freezing additional frozen layers to form acomposite layer having a thickness of the order of .05 to .25".

4. The method of freezing coffee having solids of order of 10 percent byweight and the remainder water which comprises the steps described inclaim 1 wherein each film of the fluid has a thickness of the order of.005 to .01".

'5. The method as described in c aim 2 which'includes additional stepsof depositing and spreading and freezing additional frozen layers toform a composite layer having a thickness of the order of .04" to .05".

6. In the art of freezing products, the steps of, produring asubfreezing temperature condition upon a continuous flexible surfacehaving side edges, moving said surface along a freezing path parallel tosaid side edges to a peeling zone, depositing a stream of the fluid tobe frozen onto said surface at a zone along said path spaced from saidside edges, imparting to the fluid at said zone relative motion withrespect to said surface to spread the fluid toward said side edges to apredetermined depth thereby to form a first layer of fluid, permittingsaid first layer of fluid to freeze to produce a first frozen layer,depositing a second stream of the fluid onto said first frozen layer ata second zone, imparting to the fluid at said second zone relativemotion with respect to said surface to spread the fluid toward said sideedges to a predetermined depth thereby to form a second layer of thefluid over said first frozen layer, permitting the fluid of said secondlayer to freeze and thereby to form a composite frozen layer comprisingsaid first frozen layer and said second layer, and deflecting saidsurface at said peeling zone to peel it away from said composite frozenlayer.

7. In apparatus for producing a frozen product, the combination of, aflexible metal belt presenting a freezing surface, belt-mounting meansfor said belt and including means to move said belt through a productfreezing zone, and means to deposit the product in separate zones spacedlongitudinally along said belt within said freezing zone and spreadermeans at each of said separate zones which moves to impart spreadingmovement to the product transversely of the belt thereby to form aplurality of films of the product to be frozen onto said surface at saidseparate zones along the path of said belt within said freezing zonewhereby the product is frozen into a composite layer formed by aplurality of successive frozen films, said belt-mounting means includingmeans to deflect said belt as the belt moves from said freezing zone tothereby peel the 'belt away from the product.

8. Apparatus as described in claim 7 which includes spreader means toaid in producing thin films of the product being deposited on the belt.

9. Apparatus as described in claim 8 wherein said spreader meanscomprises elongated wiper blades extending transversely of the directionof movement of said belt.

10. Apparatus as described in claim 9 which includes fluid depositingmeans to deposit a stream of the fluid onto said 'belt immediately afterthe belt has moved past each of said wiper blades.

11. Apparatus as described in claim 7 wherein said belt-mounting meanscomprises an evaporator plate having an elongated refrigerated surfaceextending through said freezing zone and of substantially uniformlongitudinal contour, a pair of mounting rollers positioned respectivelyat the ends of said refrigerated plate with the belt passing around afirst roller when moving to said freezing zone and passing around asecond roller when moving from said freezing zone, said first rollercomprlsing a driving roller for moving said belt and said second rollerbeing of lesser diameter than said first roller and flexing said beltfor the removal of the frozen product therefrom.

12. Apparatus as described in claim 11 which includes means to supplyrefrigerant to one end of said evaporator plate and to withdrawrefrigerant from the other end of said evaporator plate.

13. Apparatus as described in claim 11 which includes means to supply alubricating fluid bet-ween said evaporator plate and said belt and towithdraw the lubricating fluid downstream along the belt.

14. In apparatus for producing a frozen product, the combination of, aflexible metal belt presenting a freezing surface, belt-mounting meansfor said belt and including means to move said belt through a productfreezing zone, means to deposit a plurality of films of the product tobe frozen onto said surface at a plurality of zones along the path ofsaid belt within said freezing zone whereby the product is frozen into acomposite layer formed by a plurality of successive frozen films, saidbelt-mounting means including means to deflect said belt as the beltmoves from said freezing zone to thereby peel the belt away from theproduct, and spreader means to aid in producing thin films of theproduct being deposited on the belt comprising elongated wiper bladesextending transversely of the direction of movement of said belt, saidfluid depositing means depositing a stream of the fluid onto said 9 beltimmediately after the belt has moved past each of said wiper blades, theapparatus including mounting means for said wiper blades and means tooscillate said mounting means to move said wiper blades longitudinallyof themselves.

15. Apparatus as described in claim 14 which includes means to pass astream of subcooled air along the surface of the product passing throughand away from said freez ing zone.

16. Apparatus as described in claim 14 wherein said product is a foodproduct which is deposited in liquid form, a supply tank for the liquid,means to maintain a predetermined temperature condition of liquid withinsaid tank, pump means to withdraw liquid from said tank, and tube meansextending to each of the zones where the liquid is deposited on thebelt.

17. Apparatus as described in claim 14 wherein said mounting means is arectangular rack, and a crank arm assembly connected to oscillate saidrack.

18. The art as described in claim 1 which includes the additional stepof breaking the frozen product in a subfreezing atmosphere to formfrozen particles of the product.

19. The art as described in claim 1 which includes additional identicalsteps for freezing successive layers of the frozen product.

20. The art as described in claim 1 wherein the flexible surface is thetop surface of a moving refrigerated belt.

References Cited UNITED STATES PATENTS 1,309,995 7/1919 Bates 62-3451,528,043 3/ 1925' Bennett 6272 3,037,366 6/1962 Field 62-345 3,253,4205/1966 De George 6272 WILLIAM E. WAYNER, Primary Examiner US. Cl. X.R.

